I. Relevant Knowledge of High-Speed Counting
The frequency of the input pulse can be read by the PRV instruction to measure the frequency of the high-speed counter. The measured frequency is output in Hz as an 8-bit hexadecimal value and can only be used in high-speed counter 0. In addition, the frequency can be measured while the comparison operation of high-speed counter 0 is being performed. Even during frequency measurement, the functions of the high-speed counter and pulse output will not be affected. 1. High-speed counter frequency measurement steps (1) Setting the use/non-use of the high-speed counter: Set the PLC system setting [High-speed counter 0 use/non-use] to "use". (2) Counter selection: Set [high-speed counter]/[pulse input mode] in the PLC system settings. (3) Selection of value range mode: Select [high-speed counter 0]/[value range mode] in the PLC system settings. If the value range mode is set to ring mode, select [high-speed counter 0]/[ring counter maximum value] in the PLC system settings. (4) Selection of the reset method of the current value of the high-speed counter: Select [high-speed counter 0]/[reset method] in the PLC system settings. (5) Execution of PRV instruction: Operand N is the sequence number of the high-speed counter [high-speed counter input 0: #OO1O]; Operand C is the frequency read, which is #0003; Operand D is the frequency storage channel. 2. Specifications The specifications of the high-speed counter used for frequency measurement are shown in the table below.
II. Relevant Knowledge of Analog Quantities
In addition to software calculations, analog programming often requires some hardware configuration.
Examples include selection of current and voltage signals, resolution selection, and channel selection.
As shown in the image below.
Connect the built-in analog signal wires according to the wiring requirements.
Then you need to set whether the analog signal is a current input or a voltage input.
The four DIP switches shown in the image above.
See the image below for specific settings.
After completing these hardware steps, you need to find the corresponding settings in the software programming interface and configure them in the software.
Parameters such as whether the channel is selected, whether the resolution is 6000 or 12000, and whether the range is 4-20mA or 0-5V, etc.
Only after the above settings are correct can we perform the relevant simulation calculations, conversion of engineering quantities, etc.
Otherwise, it's all in vain; no matter how well the program statements are written, it's useless.
III. Password Settings ① Encryption
In the CX-P programming software workspace, right-click "New PLC", select "Properties" - "Protection", and enter an 8-digit password in the UM read protection password field, as shown in the following figure:
Then download the program to the PLC, and finally select "Protection" - "Set Password" in the " PLC " drop-down menu.
②Release:
After the CX-P software establishes online communication with the PLC, select "Protection" - "Release Password" in the "PLC" drop-down menu, and enter the password.
*Note:
If a programmer does not want the encrypted program to be overwritten by other users' programs, they can check the "Disable overwriting protected programs" option in the properties. After doing this, if they want to overwrite the program in the PLC, they will need to perform the password release operation first.
